# ENDOCRINE RESPONSIVENESS IN HETEROTHERMY

> **NIH NIH K04** · UNIVERSITY OF ALASKA FAIRBANKS · 1994 · $70,200

## Abstract

The candidate plans to remain at the University of Alaska to pursue
research on his unique animal model, the hibernating arctic ground squirrel
Spermophilus parryii.  The award would enable him to increase his time
available for research from approximately 65 to 85%.  Because the
investigation of freeze resistance involves techniques and approaches in
which the candidate has not been specifically trained, receipt of an RCDA
would be especially advantageous in allowing him time to interact with
experts in cryobiology at other institutions.  The Institute of Arctic
Biology fully supports the candidate's work and offers a uniquely
appropriate situation for the studies in terms of environment and
facilities; the relative geographical isolation and small size of the
Institute, however, limit the potential for interactions unless travel is
made possible by limiting non-research responsibilities.

The proposed research investigates (I) interrelationships between the
reproductive endocrine system and control over seasonally changing body
temperatures (Tb's) in hibernating mammals, and (II) mechanisms by which S.
parryii can adopt subzero Tb's without freezing.  Aims related to
reproductive function and hibernation include:  (1) measuring plasma
reproductive hormone levels at the end of hibernation; (2) testing for CNS
sensitivity to androgen inhibition of hibernation; nd (3) determining if
plasma steroid hormone-binding proteins prevent such inhibition during
hibernation.  Aims related to freeze resistance include:  (1) determining
limits to subzero tolerance and testing blood from freeze-resisting animals
for antifreeze and cryoprotectants; (2) measuring seasonal changes in blood
supercooling points and serum proteins and lipoproteins; (3) identifying
ice nucleation factors in blood and determining if ground squirrels
eliminate these to avoid freezing; (4) artificially inoculating freezing in
supercooled animals to investigate mechanisms of freeze defense; and (5)
examining the role of nonshivering thermogenesis in stabilizing subzero
hypothermia.

These experiments should elucidate novel functional relationships between
the reproductive endocrine system and CNS control over Tb.  They address
the question of how reproductive recrudescence begins during the constant
darkness and periodic low body temperatures of hibernation.  Other
experiments investigate basic questions about apparently unique mechanisms
of freeze resistance in mammals, answers to which may relate to
cryopreservation of transplant organs and tolerance to severe hypothermia.

## Key facts

- **NIH application ID:** 2194444
- **Project number:** 5K04HD000973-03
- **Recipient organization:** UNIVERSITY OF ALASKA FAIRBANKS
- **SAM.gov UEI:** FDLEQSJ8FF63
- **Principal Investigator:** BRIAN M BARNES
- **Activity code:** K04 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1994
- **Award amount:** $70,200
- **Award type:** 5
- **Project period:** 1992-03-01 → 1997-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/2194444

## Citation

> US National Institutes of Health, RePORTER application 2194444, ENDOCRINE RESPONSIVENESS IN HETEROTHERMY (5K04HD000973-03). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/2194444. Licensed CC0.

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