The endocrine control of reproduction and molt in male and female emperor (Aptenodytes forsteri) and adelie (Pygoscelis adeliae) penguins: I. Annual changes in plasma levels of gonadal steroids and LH

doi:10.1016/0016-6480(86)90092-4

General and Comparative Endocrinology

Volume 62, Issue 1, April 1986, Pages 43-53

https://doi.org/10.1016/0016-6480(86)90092-4 Get rights and content

Abstract

Changes in plasma LH, testosterone, and estrogens were investigated throughout reproduction and molt in free-living male and female emperor (Aptenodytes forsteri) and adelie (Pygoscelis adeliae) penguins. In both sexes and species, plasma LH and gonadal steroids were severalfold above basal level at the time of arrival on the breeding grounds, suggesting that environmental cues (especially decreasing daylength in emperors) rather than mating and courting primarily stimulate gonadal development and reproduction. In both species a marked increase in plasma LH (both sexes), testosterone (males), and estrogens (females) corresponded with the time of maximum gonadal size, and peak values were obtained at the time of copulation, i.e., in emperors about 10–15 days prior to egg laying. In females, plasma LH and estrogens dropped to low levels between copulation and egg laying. Similarly, following copulation in males plasma testosterone fell to lower levels that in emperors were maintained during incubation and brooding of the non-thermally emancipated chick. Plasma LH levels followed the same trend as testosterone, falling after copulation and falling further prior to molt. Though lower than at copulation, plasma LH was higher in incubating (males) and brooding (males and females) emperors than during rearing of the thermally emancipated chicks, suggesting that plasma LH might be related to incubating, brooding, and territorial behavior. In male and female emperors and in male adelies, plasma gonadal steroids and LH were at basal levels throughout molt.

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The endocrine control of reproduction and molt in male and female emperor (Aptenodytes forsteri) and adelie (Pygoscelis adeliae) penguins: I. Annual changes in plasma levels of gonadal steroids and LH

Abstract

Mol. Cell. Endocrinol

Gen. Comp. Endocrinol

Horm. Behav

Gen. Comp. Endocrinol

Gen. Comp. Endocrinol

Gen. Comp. Endocrinol

Comp. Biochem. Physiol

Comp. Biochem. Physiol

Gen. Comp. Endocrinol

Gen. Comp. Endocrinol

Gen. Comp. Endocrinol

Gen. Comp. Endocrinol

Penguin chicks hatched at San Diego Institute

U.S. Antarct. J

Experimental studies on the annual cycles of thyroid and adrenocortical functions in relation to the reproductive cycle of drakes

J. Physiol. Paris

Annual endocrine cycles and environment in birds with special reference to male ducks

Adaptative aspects of endocrine regulations in birds

Circadian and circannual hormonal rhythms

Seasonal changes in plasma concentrations of LH in lesser snow geese (Anser caerulescens)

Biol. Reprod

Environmental manipulation of seasonal reproduction in spotted munia Lonchura punctulata

Molt, T4, and testosterone in adult male and female bar-headed geese, Anser indicus

Canad. J. Zool

Photoperiodic controls in the secretion of gonadotropins in birds

Amer. Zool

Molt, T₄, and testosterone in adult male and female bar-headed geese, Anser indicus