Journal article
Regulation of Yolk-Androgen Concentrations by Plasma Prolactin in the American Kestrel
Hormones and behavior, Vol.40(4), pp.462-471
12/2001
Handle:
https://hdl.handle.net/2376/112894
PMID: 11716575
Abstract
The concentrations of maternally derived androgens in the yolks of avian eggs vary within and among clutches, but a mechanistic basis for this variation has not been elucidated. We investigated in the American kestrel, Falco sparverius, whether changes in plasma-prolactin concentrations induced by changes in photoperiod and food supply affect yolk-androgen concentrations. Over the course of a photoinduced breeding period in the laboratory, we measured concentrations of plasma immunoreactive prolactin (ir-prolactin) in female kestrels with ad libitum food availability (control) or food availability that was reduced during the early breeding period. In a second laboratory study, we administered via osmotic mini-pumps ovine prolactin (o-prolactin) to females beginning on the day they laid their first egg of a clutch (egg-day 1) to determine the effects of high prolactin concentrations on yolk-androgen concentrations. In both this study and one on free-living kestrels, we quantified changes in yolk-androgen concentrations with date of clutch initiation. Concentrations of ir-prolactin in nonlaying females rose with date, irrespective of food treatment. Egg-day 1 ir-prolactin concentrations were higher in control females laying late during the breeding phase than in those laying early. This increase was absent in food-reduced females. Yolk-androgen concentrations in eggs 3 and 4 but not eggs 1 and 2 of the clutch were higher in clutches initiated late than in clutches initiated early in the breeding phase in both the field and laboratory. o-Prolactin treatment elevated yolk-testosterone but not androstenedione concentrations. These findings suggest that, in American kestrels, seasonal and laying-associated increases in plasma-prolactin concentrations elevate yolk-testosterone concentrations. Food availability and other factors may interact with date to regulate the effects of prolactin on yolk-testosterone deposition.
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Details
- Title
- Regulation of Yolk-Androgen Concentrations by Plasma Prolactin in the American Kestrel
- Creators
- Keith W Sockman - School of Biological Sciences, Center for Reproductive Biology, Washington State University, Pullman, Washington, 99164-4236Hubert Schwabl - School of Biological Sciences, Center for Reproductive Biology, Washington State University, Pullman, Washington, 99164-4236Peter J Sharp - Division of Integrative Biology, Roslin Institute, Roslin, Midlothian, EH25 9PS, United Kingdom
- Publication Details
- Hormones and behavior, Vol.40(4), pp.462-471
- Academic Unit
- Biological Sciences, School of
- Publisher
- Elsevier Inc
- Identifiers
- 99900547842201842
- Language
- English
- Resource Type
- Journal article