Effect of particle size on the prolonged action of subcutaneous danazol in male and female rats.
OBJECTIVE
To investigate the effects of two different particle sizes of danazol in male and female rats.


METHODS
Prospective, vehicle-controlled study.


METHODS
Undergraduate college research facility and medical research laboratory.


METHODS
18 castrated male rats and 18 cycling female rats.


METHODS
Preparations of danazol with particle sizes of 2.05 microm or 5.2 microm were administered as a single subcutaneous injection of 400 mg/kg to castrated male rats or estrus-cycling females.


METHODS
Serum LH level in males and estrous cycle length in females.


RESULTS
In males, both preparations significantly (P<. 001) suppressed serum LH by day 5 of treatment. Gonadotropin levels remained low throughout the 35-day study in rats that received the larger-particle danazol, whereas LH levels began to increase after 25 days in rats that received smaller-particle danazol. In females, the normal 4- to 5-day estrous cycle interval was prolonged to 38.7 days (P<.001) in those that received the larger-particle danazol and 25.5 days in those that received the smaller-particle danazol.


CONCLUSIONS
The results demonstrate the prolonged effectiveness of a single subcutaneous dose of danazol and indicate that one might be able to predict the effective duration of activity by changing the particle size of the danazol administered.
Butterstein
G M
GM
Department of Biological Sciences, Union College, Schenectady, New York 12308, USA. buttersg@union.edu
Castracane
V D
VD
D000279:Administration, Cutaneous; D000818:Animals; D003613:Danazol / Q000008:administration & dosage*; D004965:Estrogen Antagonists / Q000008:administration & dosage*; D004971:Estrus / Q000187:drug effects*; D005260:Female; D006062:Gonadotropins / Q000097:blood; D007986:Luteinizing Hormone / Q000097:blood*; D008297:Male; D009919:Orchiectomy; D010316:Particle Size; D011446:Prospective Studies; D051381:Rats
D004965:Estrogen Antagonists; D006062:Gonadotropins; D007986:Luteinizing Hormone; D003613:Danazol