Ram sexual pheromone: first approach of chemical identification.
A series of experiments has been designed with the aim of identifying the pheromone of the ram responsible for the primer effect--induction of a LH peak and ovulation--in anoestrous ewes. In a first experiment, the pheromonal activity of various sources was tested, extract of ram fleece and ante orbital gland secretion induced characteristic changes in LH secretion, whereas urine was ineffective. A second experimental series showed that an accurate separation of the ram's fleece extract in acid and neutral fractions resulted in each case in a complete loss of activity whereas both together were efficient, indicating that the pheromonal action involves several components. From GC-MS analysis of both fractions, and after comparison of male and female wool extract, semi-synthetic formulations were tested. The association of synthetic 1,2-hexadecanediol and 1,2-octadecanediol with the natural acid fraction was efficient in stimulating LH release in anoestrous ewes. As the most frequent linear fatty acids have been shown not to be necessary, a role of branched and oxygenated fatty acids has been hypothesised.
Cohen-Tannoudji
J
J
Inra Laboratoire de Comportement Animal, Nouzilly F-37380 France.
Einhorn
J
J
Signoret
J P
JP
D000818:Animals; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D010060:Ovulation / Q000502:physiology; D012724:Sex Attractants / Q000737:chemistry* / Q000502:physiology; D012726:Sexual Behavior, Animal / Q000502:physiology*; D012756:Sheep / Q000502:physiology*; D014935:Wool / Q000737:chemistry
D012724:Sex Attractants; D007986:Luteinizing Hormone