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The present study reports the presence of progesterone, testosterone and 17 beta-estradiol and their corresponding binding proteins in the reproductive system of Octopus vulgaris Lam (phylum Mollusca, subphylum Cephalopoda). These sex hormones occur in testis, vas deferens, seminal vesicle, prostate and Needham's sac. The hemolymph also contains a small, but significant, amount of these hormones and their carrier proteins. Among various tissues of the reproductive system, the seminal vesicle possesses the highest concentration of progesterone (4.8 ng/g tissue). The testis is the organ which contains the highest amount of testosterone (5.2 ng/g) whereas the prostate is the organ which contains the highest amount of 17 beta-estradiol (0.92 ng/g). The presence of these hormones has been ascertained by a radioimmunoassay method, an immunoenzymatic method and by a chemical (HPLC) method. Seatchard studies indicated that vas deferens and seminal vesicle contain specific sex steroid binding molecules at affinity levels comparable to those of vertebrate steroid receptors (0.5-5.0 pmol/g protein). In addition to the presence of the hormones, the delta 5,3 beta hydroxysteroid dehydrogenase, the key enzyme of steroidogenesis, also is found in testis. From a phylogenetic point of view, these findings are very interesting because they indicate a common origin of a sex hormonal system between Mollusca Cephalopoda and Vertebrates.

The release of PGF2 alpha and PGE2, progesterone, androgens and oestradiol in vitro, and the aromatase activity in the brain of the male lizard Podarcis sicula sicula during three different phases of the reproductive period were evaluated. In addition, the effects of salmon GnRH, substance P, salmon GnRH antagonist, substance P antagonist, PGF2 alpha, PGE2 and acetylsalicylic acid on the release of prostaglandins and sex steroids and on aromatase activity in the brain were evaluated during the same three phases. PGF2 alpha, oestradiol and aromatase activity were higher during the refractory phase, androgens during the fighting phase, and progesterone during the mating phase, while PGE2 was lower during the refractory phase. Treatment with salmon GnRH increased PGF2 alpha, oestradiol and aromatase activity, but decreased the amount of androgens released. Substance P decreased PGF2 alpha, oestradiol and aromatase activity, but increased the amount of androgens released. PGF2 alpha increased oestradiol and aromatase activity, but decreased the amount of androgens released. Acetylsalicylic acid decreased PGF2 alpha, oestradiol and aromatase activity, but increased the amount of androgens released. These data suggest that salmon GnRH and substance P have different roles in reproductive processes, with opposite mechanisms, in the central nervous system of this male lizard: salmon GnRH seems to be involved in regulating the refractory phase, while substance P plays a role in regulating the fighting phase.

The release in vitro of prostaglandin F2 alpha (PGF2 alpha), prostaglandin E2 (PGE2), progesterone, androgens and estradiol-17 beta by the corpora lutea (CL) of the oviparous lizard, Podarcis s. sicula, was studied. In addition, the in vitro effects of PGF2 alpha and PGE2 on sex steroid release by CL were evaluated. Corpora lutea were divided into four types, according to their different developmental stage: CL1 (unshelled eggs in the oviduct); CL2 (shelled eggs in the oviduct); CL3 (eggs laid 6 h previously); CL4 (eggs laid 48 h previously) and were placed into culture. PGF2 alpha secretion was highest in CL4 incubated samples and lowest in CL2 and PGE2 was highest in CL1 and CL2. Progesterone secretion was highest in CL2 and lowest in CL4; androgens were not detectable and estradiol-17 beta secretion was highest in CL2. PGF2 alpha decreased progesterone secreted by CL1, CL2 and CL3, while it did not modify release of androgens and estradiol-17 beta. PGE2 did not affect sex steroid release. These data suggest a role of PGF2 alpha in inducing luteolysis, while PGE2 could be implied in the maintenance of CL. A role of progesterone during gestation of Podarcis s. sicula was also confirmed.

The present investigation was performed to evaluate the effects of mammalian gonadotropin-releasing hormone (mGnRH) on prostaglandin F2 alpha (PGF2 alpha) plasma level in adult male and female water frog, Rana esculenta, during three different periods of the reproductive cycle: recovery period (October), breeding period (May), and postreproductive period (June). Intact, hypophysectomized (HYP), gonadectomized (GON), and hypophysectomized-and-gonadectomized (HYP/GON) animals were injected with 0.6 micrograms of mGnRH and sacrificed 1 hr and 5 hr after peptide administration. Some of each of the groups were sacrificed without having received mGnRH. PGF2 alpha plasma levels were assessed by radioimmunoassay. Hypophysectomy induced a significant increase of PGF2 alpha levels in October and June males. mGnRH induced a significant increase of PGF2 alpha plasma levels only in HYP and HYP/GON frogs. The tissue target of this GnRH action is, at present, unknown, although interrenals could be putative responsive tissues. At present, it is also difficult to assign any physiological role to observed phenomena unless to suppose that the pituitary inhibition is not constant throughout the year. It cannot be excluded that the prostaglandin induction depends on a local paracrine action of GnRH, which could be performed outside any pituitary control.

Plasma patterns of prostaglandin F2 alpha (PGF2 alpha) and sex hormones (progesterone, androgens and 17 beta-estradiol) have been studied in the female crested newt, Triturus carnifex (Laur.), during the annual sexual cycle. The effects of exogenous PGF2 alpha on sex hormones were determined. In addition, the effects of one week's captivity on plasma PGF2 alpha and sex hormones were reported. PGF2 alpha plasma level peaked in April, was low in summer, and progressively increased during the autumn to peak again in December. The April PGF2 alpha coincided with a 17 beta-estradiol rise, and with a progesterone drop. The autumn PGF2 alpha increase was coupled to a 17 beta-estradiol rise, and therefore it has been tentatively related to ovary and oviduct development. In newts collected in April, moreover, a PGF2 alpha-dependent 17 beta-estradiol synthesis could occur, since PGF2 alpha injection induced a significant 17 beta-estradiol plasma increase. These findings led us to suppose that PGF2 alpha intervenes in spring breeding season termination through the induction of a 17 beta-estradiol synthesis as in other amphibian species. PGF2 alpha injection caused a progesterone decrease, probably by inducing corpora lutea lysis. The patterns of plasma sex hormones were consistent with the results reported for the same newt species.

Prostaglandin F2 alpha (PGF2 alpha), progesterone, androgens (testosterone + dihydrotestosterone), and 17 beta-estradiol were measured in the plasma of male frogs, Rana esculenta, by radioimmunoassays. Plasma concentrations of PGF2 alpha were higher from October to December and peaked in March (prereproduction) and in June (postreproduction). Plasma progesterone levels were relatively low but showed an increase from October to December and in June. Plasma androgen titres rapidly increased in early spring, started to fall during the reproductive period (May), and were lowest in July. 17 beta-Estradiol levels peaked in March and in June. The annual profile of the plasma PGF2 alpha levels was positively correlated with those of progesterone and androgens, while it was not correlated to the estradiol plasma pattern, except in March and June. The increase in plasma PGF2 alpha in the autumn may be related to gonadal recovery. The simultaneous increases in PGF2 alpha and 17 beta-estradiol, both in March and June, suggest a PGF2 alpha-dependent estradiol synthesis, a possibility also supported by the increased plasma 17 beta-estradiol previously observed in PGF2 alpha-treated postreproductive females. The effects of captivity and castration on plasma PGF2 alpha concentrations were also studied during the annual cycle. Captivity was associated with a reduced PGF2 alpha titre, while castration did not modify prostaglandin synthesis, which may point to an extragonadal source of plasma PGF2 alpha.

Plasma patterns of prostaglandin F2 alpha (PGF2 alpha) and sex hormones (progesterone, androgens and 17 beta-estradiol) have been studied in the male crested newt, Triturus carnifex (Laur.), during the sexual cycle. The effects of exogenous PGF2 alpha on sex steroids have also been observed. In addition, effects of one week's captivity are reported. The patterns of plasma sex hormones, during the annual cycle, are consistent with the results previously reported for the same newt species. PGF2 alpha plasma level peaks in April, is low in summer, and progressively increases during autumn to peak again in December. The April PGF2 alpha peak coincides with a plasma estradiol increase and with an androgens drop. In April-collected newts, moreover, PGF2 alpha treatment induces a significant estradiol increase. These findings lead us to suppose that at the end of the breeding season (April) a PGF2 alpha-dependent estradiol synthesis occurs which could be implied in reproductive period termination. In several vertebrates, including some amphibian species, in fact, chronic administration of estradiol results in a strong inhibition of testicular endocrine tissue activity. The putative role of PGF2 alpha-dependent estradiol production in the gonadal regulation in amphibia living in temperate zones is discussed. The autumn PGF2 alpha increase has been tentatively related to the recovery gonadal processes and secondary sexual character development.

Progesterone, 17-hydroxyprogesterone, androstenedione, 5 alpha-dihydrotestosterone, dehydroepiandrosterone, testosterone and oestradiol concentrations in the plasma were measured by simultaneous radioimmunoassay in males of the lizard Podarcis s. sicula. Hormonal determinations were performed at monthly intervals from January to December (except for August). Testosterone and androstenedione reached peak values of 174.8 ng/ml and 21.4 ng/ml in the mating season (spring) and then testosterone fell abruptly to 5.9 ng/ml in June remaining at this level during hibernation when dehydroepiandrosterone (DHA) reached a maximal level of 28.5 +/- 9.3 ng/ml. Castration resulted in a marked decrease of testosterone, androstenedione, dihydrotestosterone and DHA values, with DHA being significantly lowered only during the winter season. In castrated animals, however, testosterone and androstenedione persisted conspicuously in the plasma during the breeding period, suggesting that adrenal sex steroid output may change during the annual reproductive cycle. In intact animals, progesterone and oestradiol exhibited peak values during the refractory period after the mating season. We suggest a probable role of oestradiol in the induction of the refractory period in this lizard.

Prostaglandin F2 alpha (PGF2 alpha) and sex hormones (progesterone, androgens, and estradiol-17 beta) have been determined in the plasma of female water frog, Rana esculenta, utilizing radioimmunoassay methods (RIA). Plasma PGF2 alpha level increases in autumn-winter when recovery processes interest both gonad and oviduct. The PGF2 alpha plasma highest value has been recorded in October (4.52 +/- 0.58 ng/ml) and the lowest in May (1.43 +/- 0.12). The PGF2 alpha annual pattern is positively correlated to that of estradiol (but not to those of progesterone and androgens). Exogenous PGF2 alpha, injected into intact females during the various phases of the annual cycle, induces an increase of ovarian weight in frogs treated in December and February and an increase of plasma estradiol in postreproductive animals (June). Although preliminary, such results propose a putative implication of PGF2 alpha in ovarian recovery processes and in the interruption of reproductive processes in late summer.

A specific nuclear protein (SNP) appears in the oviduct of the lizard, Podarcis s. sicula Raf., during the recovery phase of the breeding cycle. The protein has a low molecular weight (9.9 kDa), a high electrophoretic mobility and a peculiar amino acid composition. It seems to be regulated by estradiol which, in this species, is involved in oviduct stimulation. Nuclear poly(ADPribose)transferase activity increases in the oviduct as the organ grows, and it peaks upon morphological maturation. Thereafter, as the oviduct becomes secretory, the enzyme returns to basal level. A transient increase of poly(ADPribose)transferase precedes the appearance of SNP, which suggests that the two phenomena are related.

In the ovoviviparous teleost, Poecilia reticulata, the esterases give rise to around 13 variants when separated by electrofocusing. These variants show histochemical characteristics (e.g. substrate utilization and sensitivity to inhibiting substances) which can be related to postnatal developmental stages and to adult sex. A few variants, moreover, appear to be typical of the stage examined (newborn, young, adult male and female). Very few variants can be classified by the criteria of Masters and Holmes (1975).

The uptake of radioactivity by ovary, oviduct and thigh muscles of the lizard, Lacerta s. sicula, after administration of labeled mammalian gonadotropins has been followed. Ovary and oviduct show a significantly higher radioactivity than thigh muscles. The ovarian uptake, moreover, is decreased by the corresponding non-labeled gonadotropin. The meaning of these observations for the physiological regulation of reproductive processes in that lizard, are discussed.

1. The effect of estradiol and pituitary hormones on the titre of serum vitellogenin has been studied in Rana esculenta by rocket immunoelectrophoresis. 2. Hepatic synthesis of vitellogenin depends on physiological doses of estradiol. 3. Gonadotrophins enhance the uptake, presumably by acting directly on the oocyte plasma membrane. 4. In addition, our data support direct pituitary intervention on liver synthesis and/or release of vitellogenin. 5. Hormonal response, as evaluated by vitellogenin serum titres, tends to increase from November to July. This could be the expression of a modification, throughout the sexual cycle, of liver sensitivity to the hormones.

In the male New Zealand rabbit, esterases and phosphatases of several sex accessory organs undergo some modifications at the beginning of the puberal period. The esterases show, by electrofocusing, a certain degree of multiplicity and therefore give rise to different bands whose number and relative activity change in relation to puberty in the epididymis, prostate and prepuce skin. High enzyme multiplicity is also shown by the perineal and the anal glands. Some bands are, in several of these organs, under the control of testicular hormones. The alkaline and acid phosphatases resolve by electrofocusing into a limited band number. The behaviour of these enzymes during postnatal life is complex and seems to be related to both morphological development and physiological activity of the various organs. The possible correlations between enzyme modifications and sex accessory organ maturation are discussed.

1. Liver esterases of the green frog Rana esculenta have been fractionated on disc electrophoresis, thin-layer electrofocusing and column electrofocusing. 2. The enzyme resolves in several molecular forms some of which result sex dependent, since they disappear in castrated animals and can be induced by sex hormone administration. 3. The enzyme molecular forms which depend on female hormones might be involved in cellular modifications of hepatocytes related to yolk protein synthesis. induced by sex hormone administration. 3. The enzyme molecular forms which depend on female hormones might be involved in cellular modifications of hepatocytes related to yolk protein synthesis.