instruction:
Given an abstract of a paper, generate a title for this paper such that conveys the key focus of the paper.
question:
Abstract: It has been postulated that increased energy expenditure results in shortened survival. To test this "rate-of-living theory" we examined the effect of raising energy expenditure by means of cold exposure on the longevity of rats. Male 6-mo-old SPF Long-Evans rats were gradually accustomed to immersion in cool water (23 degrees C). After 3 mo they were standing in the cool water for 4 h/day, 5 days/wk. They were maintained on this program until age 32 mo. The cold exposure resulted in a 44% increase in food intake (P less than 0.001). Despite their greater food intake, the cold-exposed rats' body weights were significantly lower than those of control animals from age 11 to 32 mo. The average age at death of the cold-exposed rats was 968 +/- 141 days compared with 923 +/- 159 days for the controls. The cold exposure appeared to protect against neoplasia, particularly sarcomas; only 24% of the necropsied cold-exposed rats had malignancies compared with 57% for the controls. The results of this study provide no support for the concept that increased energy expenditure decreases longevity.
answer:
Longevity of cold-exposed rats: a reevaluation of the "rate-of-living theory".

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Abstract: A modification of Patterson's external antro-ethmoidectomy operation is described which provides a more direct and simpler approach than the transantral operation for decompression of the orbit.
answer:
The Patterson operation for decompression of the orbit.

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Abstract: The effect of 17 beta-estradiol (17 beta E2) on anterior pituitary dopaminergic receptor (D2) content was studied in vitro in relation to PRL secretion. Anterior pituitaries from ovariectomized rats were incubated for short periods in medium 199, with or without the steroid. Dopamine (DA) receptors in partially purified pituitary membranes were quantified by equilibrium binding using [3H]spiperone; the PRL released into the incubation medium was analyzed by RIA. Addition of 10(-10) to 10(-6) M 17 beta E2 to the incubation medium of anterior pituitaries rapidly and reversibly decreased the number of DA receptors (P less than 0.01 to 0.001), while increasing PRL release, in a dose-related fashion. The maximal effect on both receptor numbers and PRL secretion was obtained with 10(-8) M 17 beta E2. This effect involved no change in receptor affinity (Kd = 0.11 +/- 0.01 nM in presence or in absence of 17 beta E2). This estrogen-induced decrease in DA-binding capacity was apparently not the result of the occupation of spiperone binding sites by the steroid, since after a 30-min incubation with 10(-8) M [3H]17 beta E2, no radioactivity was detectable on the partially purified membranes. Moreover, the presence of 17 beta E2 at the same time as the labeled D2 ligand did not modify the kinetics of association or dissociation of spiperone with pituitary membranes. This decrease in anterior pituitary DA receptor content and the increase in PRL release were already significant after a 7-min incubation in the presence of 10(-8) M 17 beta E2. Finally, these effects of 17 beta E2 were not mimicked by its 17 alpha-stereoisomer, nor by progesterone, or testosterone. These results suggest that the stimulatory effect of 17 beta E2 on PRL secretion may be due, at least in part, to the desensitization of anterior pituitary cells to DA. The steroid may produce this desensitization directly by decreasing the number of D2. The short latency of this effect likely discards the possibility of a genomic action of 17 beta E2.
answer:
Direct effect of estradiol on the number of dopamine receptors in the anterior pituitary of ovariectomized rats.