Anovulatory hamster: a comparison of the effects of short photoperiod and daily melatonin injections on the induction and termination of ovarian acyclicity

Journal Article · Sun Feb 01 04:00:00 EST 1981 · J. Exp. Zool.; (United States)

DOI:https://doi.org/10.1002/jez.1402150206· OSTI ID:5344682

Stetson, M H; Hamilton, B

Cyclic female hamsters were rendered anovulatory by daily subcutaneous melatonin injections (25 microgram/0.1 ml oil) in 29 days or by transfer to a short light cycle, LD 6:18 (lights 1000-1600 hrs) in 33 days. Estrous cyclicity was reinitiated in these animals in 44 or 45 days following cessation of melatonin injections or transfer to long light cycles (LD 14:10, lights 0600-2000 hrs), respectively. Exposure of both groups to LD 6:18 after reinitiation of estrous cyclicity caused a second cessation of ovulation in 75 (melatonin group) or 61 (short light cycle group) days. Thus, although both treatments disrupted estrous cyclicity for nearly 6 weeks, this was not sufficient to induce photorefractoriness (failure to respond to short light cycles with continued estrous cyclicity). Rather, every animal responded to LD 6:18 and ceased ovulating. Melatonin-induced anovulatory hamsters showed daily gonadotropin release patterns identical to those reported in hamsters in other anovulatory states (lactating, prepubertal, and photoinduced anovulatory hamsters); that is, peak LH and FSH release at 1700 hrs daily.

• OSTI ID: 5344682
• Journal Information: J. Exp. Zool.; (United States), Journal Name: J. Exp. Zool.; (United States) Vol. 215:2; ISSN JEZOA
• Country of Publication: United States
• Language: English

Related Subjects

550200 -- Biochemistry
551000* -- Physiological Systems
59 BASIC BIOLOGICAL SCIENCES
AMINES
ANIMALS
AZOLES
BIOCHEMISTRY
BIOLOGICAL EFFECTS
BODY
CHEMISTRY
ESTROUS CYCLE
FEMALE GENITALS
GONADOTROPINS
GONADS
HAMSTERS
HETEROCYCLIC COMPOUNDS
HORMONES
INDOLES
MAMMALS
MELATONIN
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
OVARIES
PEPTIDE HORMONES
PHOTOPERIOD
PITUITARY HORMONES
PYRROLES
RHYTHMICITY
RODENTS
SENSITIVITY
TRYPTAMINES
VERTEBRATES