[Destabilizing effect of chicken selection using the functional adrenal reserves criteria]. / Destabiliziruiushchii éffekt otbora kur po funktsional'nym rezervam nadpochechnikov.

Chicken lines produced by divergent selection for the functional adrenal reserves showed significant between-line differences in the content of corticosterone and other hormones (thyroxin, progesterone), as well as in body weight, early maturation, and egg yield. DNA fingerprinting with the pGB725 probe revealed molecular changes in genomic DNA of the chicken lines subjected to plus and minus selection. The genetic distances between the original population and the selected chicken lines, which were estimated from the molecular hybridization patterns, reflected the history of breeding. Analysis of mixed DNA from several individuals of each line revealed specific hybridization bands that could serve as DNA markers during selection for the high and low corticosterone levels in blood.

The effect of arginine-vasotocin on the production of steroid hormones by mouse, cow, and chicken ovarian tissues in vitro.

The effect of arginine-vasotocin (50 ng ml-1) on the in vitro production of progesterone, testosterone, and oestradiol by isolated cow and chicken ovarian follicles and mouse ovaries was studied. This peptide (1) enhanced the release of progesterone into the medium by the ovarian tissues of all three species of animal; (2) inhibited the production of oestradiol by mouse and cow ovaries; (3) had no significant effect on testosterone secretion in any of the species studied. The results obtained indicate that arginine-vasotocin directly influences steroid production in mammalian and avian gonads.

[Release of steroid hormones in vitro by ovarian follicles of various degrees of maturity in hens and cows]. / Vydelenie steroidnykh gormonov in vitro ovarial'nymi follikulami raznoi stepeni zrelosti u kur i korov.

The growth of ovary follicules was accompanied by a considerable decrease in the secretion of progesterone, testosterone and estradiol, as well as by a decrease of the estradiol share in total hormone production,--both in hens and in cows. The hens also revealed a decrease of the testosterone share and an increase of the progesterone share in total hormone production. the data obtained suggest a functional atresia of the ovary follicules in hens as well as in mammals. the hen mature follicules, however, differ from those of mammals in that the progesterone secretion is higher in them as compared with other steroids, the progesterone being the main ovulatory hormone in birds.

[Hormonal interrelations in the hypophyseal-ovarian system in heifers during prostaglandin F2-alpha-induced estrus]. / Gormonal'nye vzaimootnosheniia v sisteme gipofiz-iaichniki u telok v period éstrusa, indutsirovannogo prostaglandinom F2 alpha.

Study of prostaglandin F2 alpha action, synchronizing the estrus, in experiments on heifers demonstrated that Estrumeit (made by ICI, Great Britain), rostaglandin F2 alpha drug, in a dose of 500 micrograms was an active luteolytic factor, leading to the corpus luteum regress, determined by a fall in the progesteron level in the peripheral blood. During the estrus induction there was a short-term elevation in production and excretion of testosterone, this pointing to the prostoglandins participation in the activation of the androgenic ovarian function. Prolactin hyposecretion was shown to be a necessary condition for the realization of general biological processes for the occurrence of estrus.